Nematic wedge-shaped

J.H. Wild, K. Bartle, M. O Neill, S.M. Kelly and R.P. Tuffin, Synthesis and mesomorphic behaviour of wedge-shaped nematic liquid crystals with flexoelectric properties, Liq. Cryst. 33(6), 635-644, (2006). 

Interference Method for Wedge-shaped Nematic Samples... 

Recognition of the flexoelectric effect is due to Meyer [18], who in 1969 derived an expression equivalent to Eq. (97). He also had a helpful molecular picture of the effect, as illustrated in Fig. 34 a. To the left in this picture, the unstrained nematic structure is shown with a horizontal director in the case of wedge-shaped and crescent-shaped molecules. To the right the same molecules are shown adjusted in their distribution corresponding to a splay and a bend distortion, respectively. In either case the distortion is... 

Figure 5-20. Microscopy in the nematic phase of OC 2. a) Homeotropic 4/U.m cell b) wedge-shape cell with homeotropic surface treatment c) opening of the isogyres on cooling the dark nematic domain in b), sample temperature from left to right of 204, 202, 201, and 200° C. Figure reprinted with permission from L. A. Madsen, T. J. Dingemans, M. Nakata, and E. T. Samulski, Phys. Rev. Lett., 92, 145505 (2004). Copyright 2004 American Physical Society...

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